The use of balloon catheters with or without stents to treat strictures, stenoses, or narrowings in various parts of the human body is well known in the prior art. Devices of numerous designs have been utilized for angioplasty, stents and grafts or combination stent/grafts. Varied catheter designs have been developed for the dilatation of stenoses and to deliver prostheses to treatment sites within the body lumen.
Devices developed specifically to address the problems that arise in the treatment of stenoses at or near the site of a bifurcation of a body lumen are known in the art. Examples of catheters for use in treating bifurcated lumens or delivery systems for bifurcated endoluminal prostheses are shown in U.S. Pat. No. 5,720,735 to Dorros, U.S. Pat. No. 5,669,924 to Shaknovich, U.S. Pat. No. 5,749,825 to Fischell, et al., and U.S. Pat. No. 5,718,724 to Goicoechea et al.
Various techniques have been used to deliver multiple prostheses in order to provide radial support to both a main blood vessel, for example, and contemporaneously to side branches of the blood vessel. Further, single bifurcated stents and grafts have been developed in order to treat such conditions at the site of a branch of a body lumen. A bifurcated stent and/or graft typically comprises a tubular body or trunk and two tubular legs. Examples of bifurcated stents are shown in U.S. Pat. No. 5,723,004 to Dereume et al., U.S. Pat. No. 4,994,071 to MacGregor, and European Pat. Application EP 0 804 907 A2 to Richter, et al.
Illustrative procedures involving balloon catheters include percutaneous transluminal angioplasty (PTA) and percutaneous transluminal coronary angioplasty (PTCA), which may be used to reduce arterial build-up such as caused by the accumulation of atherosclerotic plaque. These procedures involve passing a balloon catheter over a guide wire to a stenosis with the aid of a guide catheter. The guide wire extends from a remote incision to the site of the stenosis, and typically across the lesion. The balloon catheter is passed over the guide wire, and ultimately positioned across the lesion.
Once the balloon catheter is positioned appropriately across the lesion, (e.g., under fluoroscopic guidance), the balloon is inflated, which breaks the plaque of the stenosis and causes the arterial cross section to increase. Then the balloon is deflated and withdrawn over the guide wire into the guide catheter, and from the body of the patient.
In many cases, a stent or other prosthesis must be implanted to provide permanent support for the artery. When such a device is to be implanted, a balloon catheter which carries a stent on its balloon is deployed at the site of the stenosis. The balloon and accompanying prosthesis are positioned at the location of the stenosis, and the balloon is inflated to circumferentially expand and thereby implant the prosthesis. Thereafter, the balloon is deflated and the catheter and the guide wire are withdrawn from the patient.
Administering PTCA and/or implanting a stent at a bifurcation in a body lumen poses further challenges for the effective treatment of stenoses in the lumen. For example, dilating a vessel at a bifurcation may cause narrowing of an adjacent branch of the vessel. In response to such a challenge, attempts to simultaneously dilate both branches of the bifurcated vessel have been pursued. These attempts include deploying more than one balloon, more than one prosthesis, a bifurcated prosthesis, or some combination of the foregoing.
However, simultaneously deploying multiple and/or bifurcated balloons with or without endoluminal prostheses, hereinafter individually and collectively referred to as a bifurcated assembly, requires highly accurate placement of the assembly. Specifically, deploying a bifurcated assembly requires positioning a main body of the assembly within the trunk of the vessel adjacent the bifurcation, and then positioning the independent legs of the assembly into separately branching legs of the body lumen.
Tracking a bifurcated assembly to a treatment site also presents additional challenges to the more standard PTCA procedure. For example, a bifurcated catheter must be tracked to the site as a unitary device until it reaches the bifurcation. Once it reaches the bifurcated treatment site, it must be positioned within the separate branches of the vessel. Therefore, it must be a unitary device during tracking and be a bifurcated device for treatment.
In order to achieve the foregoing objectives, two guide wires are typically required, one for placement of the assembly into each branch of the bifurcated vessel. Devices known in the prior art fail to track and position a device requiring two guide wires in an expeditious fashion by failing to prevent the entanglement of the wires or other complications which would prevent proper placement of the assembly and/or a smooth withdrawal the catheter and of the guide wires.
Further, devices known in the prior art fail to provide a bifurcated assembly, the distal portion of which functions as a unitary device during tracking and as a bifurcated device for positioning and deployment.
In view of the foregoing, it is an object of this invention to provide improved catheters and methods for use with multiple guide wires for delivering balloon catheters and prostheses designed to treat stenoses at or near a bifurcation of a body lumen.